Field of the Invention
The invention relates to a housing configuration for a printed circuit board equipped with components, including a housing with at least partially metallic housing walls as well as at least one metallic spring profile element, the spring profile element having a first and a second profile leg connected to one another forming an essentially V-shaped profile cross section, the first profile leg being electrically connected to a ground terminal of the printed circuit board, and the second profile leg exerting an elastic spreading force as it bears against the housing wall and makes electrical contact with the latter.
In many areas of technology, electrical equipment must satisfy increasingly more stringent requirements with regard to electromagnetic compatibility (EMC). A measure which is already known for that purpose is electrically connecting a ground terminal of a printed circuit board (EMC ground) to a metal housing that accommodates the printed circuit board, and achieving electromagnetic shielding as a result thereof.
European Patent Application 0 557 545 A1 describes a housing for equipment appertaining to electrical communications technology, which has a chamber-like structure created by inner housing walls. The electromagnetic shielding by the housing is achieved by virtue of the fact that contact strips are provided on the printed circuit board. Profiles of the contact strips correspond to contours of the chamber walls. The contact strips are provided with contact springs which project upward in an inclined manner and contact pins that are bent away perpendicularly downward. That solution is structurally complex and requires high dimensional stability for the fitting of the contact strips. Moreover, it is disadvantageous that the contact strips have to be attached to the printed circuit board before the latter is inserted into the housing.
German Utility Model G 91 09 072.5 describes a housing for a hand-held radio telephone, in which the electromagnetic shielding is effected by a metallic shielding plate which covers the printed circuit board. The shielding plate has feathered edges which make electrical contact with the housing shell when the latter is put in place.
A housing configuration which is constructed as set forth initially above is described in International Patent
Application WO 96/19098. In order to ground a circuit board, that document proposes the use of a U-shaped spring element which is fixed by one of its legs to the circuit board, bridges a gap between the circuit board, and at the same time bears against the housing wall with its other leg. A vertex of the U in that case is disposed above the circuit board.
A further metallic grounding spring is described in German Patent DE 37 90 062 C2.